However, several Australian and British media reports said the three have been behind bars in Iran for some time.

Australia's ABC broadcaster reported that one British-Australian women has been in jail for nearly a year while a couple, a British-Australian citizen and her Australian boyfriend, were detained about 10 weeks ago.

Britain's The Times newspaper said the British-Australian woman was an academic and had been given a 10-year sentence, although the charges were not clear, dpa reported.

Ten-year terms are routinely given in Iran for spying charges.

The two women are believed to be incarcerated at the Evin prison in Tehran, the Irish Times reported. It's the same prison where a British-Iranian aid worker, Nazanin Zaghari-Ratcliffe, has been jailed since 2016 on spying charges, The Times said.

The couple were detained by the Islamic Revolutionary Guards Corps for camping in a military area around Jajrood in Tehran Province, according to BBC Persian.

The Australian government updated its travel advisory for Iran on September 9 stating 'due to the risk that foreigners, including Australians, could be arbitrarily detained or arrested,' travelers should reconsider their need to travel to the country.

The arrests come amid rising tensions between Iran and the West, in particular the United States, Australia, and Britain.

Last month, Prime Minister Scott Morrison said Australia would join a U.S.-led maritime patrol in the Strait of Hormuz.

With reporting by ABC Australia, the Irish Times, dpa, Reuters, The Times, and BBC